I'd suggest moving on, since the question wasn't really a trivia question but rather a riddle, and Eucastrophe seems to have disappeared! If they come back, perhaps the mystery of the riddle can be solved. In the meantime...

What happened in the place known as Wellinghall?

<-- Celebrating Science in the TVM!

Life is short; break the rules, forgive quickly; kiss slowly; love truly; laugh uncontrollably; and never regret anything that made you smile. Twenty years from now you will be more disappointed by the things you didn't do than by the ones you did. So throw off the bowlines, sail away from the safe harbour. Catch the trade winds in your sails. Explore. Dream. Discover.

Grab a chance and you won't be sorry for the might-have-beens. - Arthur Ransome

Just because I have the vocabulary of a well-educated sailor doesn't mean I'm not a lady.

Well, yes. But what is it most known for in the context of Middle-earth history?

<-- Celebrating Science in the TVM!

Life is short; break the rules, forgive quickly; kiss slowly; love truly; laugh uncontrollably; and never regret anything that made you smile. Twenty years from now you will be more disappointed by the things you didn't do than by the ones you did. So throw off the bowlines, sail away from the safe harbour. Catch the trade winds in your sails. Explore. Dream. Discover.

Grab a chance and you won't be sorry for the might-have-beens. - Arthur Ransome

Just because I have the vocabulary of a well-educated sailor doesn't mean I'm not a lady.

Sorry, I should have been more specific. No just any water welling up, but the source of the Entwash, a symbolic and emblematic river in the history of Calenardhon. And Wellinghall seems to have been held in respect by the Ents - it was one of Treebeard's dwellings.

Oh and Treebeard took Merry and Pippin to stay there one day during the War of the Ring.

This is all true. Not quite the answer I was looking for. Perhaps I should have been more specific. What happened to Merry and Pippin there? (Although I know you know the answer. )

<-- Celebrating Science in the TVM!

Life is short; break the rules, forgive quickly; kiss slowly; love truly; laugh uncontrollably; and never regret anything that made you smile. Twenty years from now you will be more disappointed by the things you didn't do than by the ones you did. So throw off the bowlines, sail away from the safe harbour. Catch the trade winds in your sails. Explore. Dream. Discover.

Grab a chance and you won't be sorry for the might-have-beens. - Arthur Ransome

Just because I have the vocabulary of a well-educated sailor doesn't mean I'm not a lady.

The drafts that Treebeard gave Merry and Pippin from the water there caused them to grow and their hair to turn curly.And the Entmoot which resulted in the downfall of Saruman was held not all that far away

What I'd been thinking of was Treebeard giving Merry and Pippin the Ent-draught. Anyway, you've answered the question exceedingly thoroughly, so it's definitely over to you.

<-- Celebrating Science in the TVM!

Life is short; break the rules, forgive quickly; kiss slowly; love truly; laugh uncontrollably; and never regret anything that made you smile. Twenty years from now you will be more disappointed by the things you didn't do than by the ones you did. So throw off the bowlines, sail away from the safe harbour. Catch the trade winds in your sails. Explore. Dream. Discover.

Grab a chance and you won't be sorry for the might-have-beens. - Arthur Ransome

Just because I have the vocabulary of a well-educated sailor doesn't mean I'm not a lady.